Gas mask canister



June 19, 1934. Q K EI H, STAMPE l1,963,874

GAS MASK CANISTER 'Filed Nov. 14, 1951 GKEHSampe.

Jaren/ar orney Patented June 19, 1934l GAS MASK CANISTEB Gerhard Kerl Emu Heinrich stampe, Lubeek, Germany, assignor to Bernhard Drager, Brasov,

Rumania Application November 14. 1931, serien No. 575,093 In Germany January 26, 1931 'This invention relates to a gas mask canister having a plurality of layers of different materials adapted to purify air from gas, smoke and vapor. The invention especially relates to a breathing i canister of this hind adapted to be attached directly to the face piece of a gas mask.

Usually vpurifiers of this type comprise 'either layers of activated charcoal or of adsorbing chemicals or both, contained within a casing. The

breathing resistance of small canisters which are attached directly to the face piece of a gas mask generally is rather high so that the use of an additional smoke-lter within these small casings is rendereddiflicult if n at impossible. Hitherto,

1I therefore, smoke-lters have been used only in canisters of somewhat larger dimensions and of considerable weight. Such canisters can not be fastened directly to the face piece of the gas mask "but must be attached to the bodyl of the wearer 'of the breathing apparatus and connected tothe gas mask by a flexible breathing hose.

'I'he object of this invention is to facilitate the construction of a breathing canister especially of small size in such a manner that it may contain,

il. addition to layers of activated charcoal and/or chemica1s,'a further layer of a material having smoke 'ltering qualities, without substantially increasing .the breathing resistance of the whole l device.

With this object in view the invention is represented in the accompanying drawing in which several constructional forms of,a purier showing the features of the invention are illustrated.

Fig. 1 is a vertical section through a casing containing three purifying layers.

Fig. 2 is a vertical section through a casing likewise containing three filter layers but having a modied outer form.

Fig. 3 is a vertical section through a third form of a casing enclosing two purifying layers.

Fig. 4 shows a fourth form of a casing likewise enclosing two purifying layers.

Fig. 5 is a plan view of the embodiment shown in Fig. 3.

46 In Fig. 1 the casing 1 has the shape of a truncated cone. The top of this truncated cone casing is provided with means-for attaching it directly to the face piece of a gas mask, said means consisting of a threaded extension 2 integral with the casing 1. n 'I'he base of the truncated cone is closed by a cover 3 which is removably attached to the casing 1 in the well known manner. The cover 3 is provided with openings allowing the poisoned air to enter the casing in the direction of arrow 4. 5 The puried air leaves the casing as indicated by arrow 5 after having passed through the different purifiers.

Adjacent to the air inlet end of casing 1 a filtering layer 6 is arranged consisting of fibrous material like cellulose, wadding, asbestos, felt, wool or other smoke filtering material. In the direction of the flow of the breathing air a second layer 7 follows which is separated from the layer 6 by a foraminous sheet 8. The layer '7 consists of activated charcoal or like material.- A third 35 layer 9 is arranged adjacent to the air outlet end of the casing 1 and is separated by a foraminous sheet 10 fromlayer 7. The layer 9consists of a .material having gas absorbing and retaining qualities. 0n the top of this layer a' further forami- 70.

' nous sheet 11 is placed. Between the cover 3 and the first layer 6A a foraminous sheet 12 is arranged. l

The layers 6, '7 and 9 are arranged in such a manner that the speciiic breathing resistance of the individual layers decreases in the direction of the flow of the breathing air. Moreover, their cross-sectional area as is apparent from the drawing decreases in the same direction. The term "specific breathing resistance" may be defined thus: A unit ofthe specific resistance may be designated as that resistance which a 1 centimeter-cube formed by the' purifying material oders to the air passing throughit. The smokelter 6 with the greatest specic breathing resistance at the same time -has the greatest crosssectional area. The activated charcoal layer 'I has a specific breathing resistanceand a crosssectional area which are less than the specific breathing resistance and the cross-sectional area respectively of smoke-filter 6. The specific breathing resistance and the cross-sectional area of the gas absorbing and retaininglayer 9 are still less than the specic breathing resistance and the cross-sectional area respectively of the charcoal layer '1.

By this arrangement of the purifying layers the breathing resistance of the whole canister sub'- stantially is thesame as that or but slightly in- 10o creased as compared with that of a canister of like size and. having no smoke-filter. If this arrangement is not observed and if for instance the smoke-filter would be arranged at the air outlet end of casing 1, one of the other layers being ar 105 ranged adjacent to the air inlet end of said casing, thebreathing resistance of the canister as a whole would be enlarged in an undue manner.

The breathing canister as a Whole has but a small resistance and it. is also ofcomparativery small weight and may be attached directly to the face piece of a mask.

The same object could not be obtained by increasing simply the cross-sectional area of all layers, the volume as a whole remaining the same. By such arrangement the height of the purifier and thereby its eiliciency would be minimized because for each purifying layer a certain minimum height is necessary for obtaining the desired effect. A Vsufficient filtering effect, however, may be obtained if-always keeping the volume alikea smaller cross-sectional area and a greater height of the layer is chosen.

In Fig. 2 a casing is shown which likewise generally has the shape of a truncated cone. This casing has three cylindrical portions 13, 14 and 15 and three portions 16, 17 and 18 of conical shape. The threaded connecting piece 2 is attached to the conical portion 18.

At the air inlet end of the casing the cover 3 is again provided upon which the foraminous sheet 12 is located. In this modification four ltering layers 19, 20, 2l, 22 are arranged one behind the other in the direction of the flow of the breathing air. A foraminous sheet 23 is arranged between the layers 19 and 20. A further foraminous sheet 24 is located between the layers 20 and 21. At the top of the layer 21 a foraminous sheet 25 is located. Between this and a further foraminous sheet 26 forming the base of the last layer 22, an empty space 27 is provided. The layer 22 is covered by a further foraminous sheet 28.

Also in this modification the specific resistance of the layers 19, 20, 21 and 22 decreases in this sequence, that is, in the direction of the flow of the breathing air. The shoulders provided by the steplike outer form of the casing are utilized as bearing surfaces for holding the foraminous sheets arranged between each two layers. The empty space 27 arranged between the filtering layers 21 and 22 renders the upper surface of the layer 21 and the under surface of the layer 22 fully eicient, so that the purifying elect of these layers is improved as compared with the construction not having such air space.

The smoke-lilter 19 is composed of a fibrous filtering mass like that constituting-the filtering layer 6 of Fig. 1, the layer 20 being'composed of activated charcoal, whereas the layers 21 and 22 are composed of gas absorbing and binding materials different from each other.

The modification shown in Fig. 3 comprises a casing only containing two layers 29 and 30, the layer 29- again being a filter of high specific breathing resistance. The layer 30 is composed of activated charcoal and having a small specific breathing resistance. The casing of this modification likewise is stepped and has cylindrical portions 31 and 32 and two conical portions 33 and 34. Within the conical portion 33 an air space 35 is provided. The arrangement of the parts 2 and 3 and of the foraminous sheets limiting the layers is the same as in the other modifications.

Fig. 4 shows a fourth modification somewhat similar to that of. Fig. 3 in that only two layers 36 and 37 are provided, the layer 36 being again a lter of high specific breathing resistance, whereas the layer 37 is composed of activated charcoal and has a low specific breathing resistance. The layer 36 is arranged Within a cylindrical portion 38 of the casing, whereas the layer 37 is contained within a conical portion 39 of the casing, said conical portion 39 being attached directly to the cylindrical portion 38. Also in this'lmodication the parts 2 and 3 and the arrangement of the foraminous sheets limiting the layers are the same as in the other modifications.

Instead of one of the smoke-filters 6, 19, 29, and 36 respectively, a layer of any other purifying material of high specific breathing resistance may be used. For instance, a layer of very nely granulated purifying material may be employed, which layers of course have a specially high absorbing quality.

1. A gas mask canister containing' a plurality of purifying layers arranged within a casing through which the breathing air flows, said casing generally having the shape of a truncated cone, said individual layers having different speciflc breathing resistances and different mean cross-sectional areas, the layer adjacent to the base of the truncated cone having a specific breathing resistance and a cross-sectional' area greater than all the other layers contained within said casing, the layer adjacent to the top of the truncated cone having a specific breathing resistance and a mean cross-sectional area smaller than all the other layers contained within said casing.

2. A gas mask canister containing a plurality of purifying layers arranged Within a casing through which the breathing air flows, said casing generally having the shape of a truncated cone, said individual layers having different specie breathing resistances and different crosssectional areas, the layer adjacent to the base of the truncated cone having a specific breathing resistance and a cross-sectional area greater than all the other layers contained within said casing, the layer adjacent to the'top of the truncated cone having a specic breathing resistance and a cross-sectional 'area smaller than all the other layers contained within said casing, said truncated cone-casing being subdivided in a steplike manner into portions of cylindrical shape and circular cross-section, and foraminous sheets arranged between each two of said portions for separating adjacent layers.

3. A gas mask canister comprising a plurality of purifying layers arranged within the casing each transversely to the ow of the breathing air, the specific breathing resistance and the crosssectional area of said layers decreasing in the direction of the flow of the breathing air, and air spaces arranged between adjacent layers, said air spaces each having the shape of a truncated cone.

4. A gas mask canister of generally tapering form comprising means positioned at the top of said canister for attaching said canister to a gas mask or similar appliance, more than two purifying layers arranged within said canister in a transverse direction to the flow of the air to be breathed, foraminous sheets arranged between adjacent layers and separating said adjacent layers from each other, the specific breathing'resistance of the said layers decreasing in the direction of flow of the breathingair, the cross sectional area of each layer decreasing throughout the depth of the layer, the'layer adjacent the inlet constituting a smoke removal layer, the topmost layer having less specific breathing resistance than said layer adjacent the inlet, and a foraminous cover removably attached to the base end of said canister for the purpose of closing said end.

5. A gas. mask canister having an air inlet and an air exit, a casing, more than two transverse- 15" 1y positioned purifying layers arranged within said casing through which the breathing air flows,

6. A gas mask canister containing' more than two transversely positioned purifying layers through which the breathing air flows, said individual purifying layers having different speciiic4 breathing resistances and diierent cross sectional areas, the layer adjacent to the air inlet end of the canister constituting a smoke removal layer and having relatively the greatest breathing resistance and the greatest cross sectional area, the layer adjacent to' the air outlet end of the canister having relatively the smallest breathing resistance and the smallest cross sectional area'. GERHARD KARL EMIL HEINRICH STAMPE.

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